Spinal implant system and methods of use

ABSTRACT

A bone fastener comprises a first member that defines an implant cavity. A part is disposed with the first member. A retainer is connected with the part and the first member, and includes an expandable orientation and a non-expandable orientation. A second member is connectable to the retainer and configured to penetrate tissue. Implants, systems, instruments and methods are disclosed.

TECHNICAL FIELD

The present disclosure generally relates to medical devices for thetreatment of spinal disorders, and more particularly to a surgicalimplant system including a bone fastener and a related method.

BACKGROUND

Spinal pathologies and disorders such as scoliosis and other curvatureabnormalities, kyphosis, degenerative disc disease, disc herniation,osteoporosis, spondylolisthesis, stenosis, tumor, and fracture mayresult from factors including trauma, disease and degenerativeconditions caused by injury and aging. Spinal disorders typically resultin symptoms including deformity, pain, nerve damage, and partial orcomplete loss of mobility.

Non-surgical treatments, such as medication, rehabilitation and exercisecan be effective, however, may fail to relieve the symptoms associatedwith these disorders. Surgical treatment of these spinal disordersincludes correction, fusion, fixation, discectomy, laminectomy andimplantable prosthetics. As part of these surgical treatments, spinalconstructs such as vertebral rods are often used to provide stability toa treated region. Rods redirect stresses away from a damaged ordefective region while healing takes place to restore proper alignmentand generally support the vertebral members. During surgical treatment,one or more rods and bone fasteners can be delivered to a surgical site.The rods may be attached via the fasteners to the exterior of two ormore vertebral members. This disclosure describes an improvement overthese prior technologies.

SUMMARY

In one embodiment, a bone fastener is provided. The bone fastenerincludes a first member that defines an implant cavity. A part isdisposed with the first member. A retainer is connected with the partand the first member, and includes an expandable orientation and anon-expandable orientation. A second member is connectable to theretainer and configured to penetrate tissue. In some embodiments,implants, systems, instruments and methods are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more readily apparent from thespecific description accompanied by the following drawings, in which:

FIG. 1 is a perspective view of components of one embodiment of a spinalimplant system in accordance with the principles of the presentdisclosure;

FIG. 2 is a cross section view of the components shown in FIG.

FIG. 3 is a perspective view of the components shown in FIG. 1 withparts separated;

FIG. 4 is a plan view of components of the system shown in FIG. 1;

FIG. 5 is a side view of the components shown in FIG. 4;

FIG. 6 is a plan view of the components shown in FIG. 4;

FIG. 7 is a plan view of components of the system shown in FIG. 1;

FIG. 8 is a side view of the components shown in FIG. 7;

FIG. 9 is a plan view of the components shown in FIG. 7; and

FIGS. 10, 11, 12 are cross section views of components of one embodimentof a spinal implant system illustrating assembly.

DETAILED DESCRIPTION

The exemplary embodiments of a surgical system and related methods ofuse disclosed are discussed in terms of medical devices for thetreatment of musculoskeletal disorders and more particularly, in termsof a spinal implant system including a bone fastener. In someembodiments, the spinal implant system includes an implant comprising abone fastener, such as, for example, a pedicle bone screw.

In some embodiments, the spinal implant system comprises a head assemblyincluding a part, such as, for example, a crown and a retainer that ispre-assembled with an implant receiver. In some embodiments, theretainer facilitates attachment of an implant receiver with a screwshaft in a robust connection. In some embodiments, the spinal implantsystem comprises a modular screw system including screw shaft assembliesand implant receiver/head assemblies that may be joined together duringmanufacturing or intra-operatively, such as, for example, during asurgical procedure in an operating room.

In some embodiments, the spinal implant system comprises a bone fastenerincluding a head assembly having a head, a crown, a snap ring and acollet; and a screw shaft assembly having a screw shaft. In someembodiments, the bone fastener is employed with a method of assemblythat includes the step disposing the collet in an open position with oneor more components of the head assembly. In some embodiments, the methodincludes the step of connecting the screw shaft with the collet in theopen position. In some embodiments, the method includes the step ofdisposing the collet in a closed position with the head assembly. Insome embodiments, the collet is rotated, for example, 180 angulardegrees, relative to one or more components of the head assembly to theclosed position.

In some embodiments, the crown includes a drive feature engageable witha surgical instrument from a top surface of the head assembly. In someembodiments, the crown includes one or more driving members engageablewith the collet. In some embodiments, the one or more driving membersare engageable with a surgical instrument to rotate the crown. In someembodiments, the collet includes one or more receiving notches thatengage the one or more driving members of the crown for rotation of thecollet. In some embodiments, the collet includes one or more slots thatallow a head of a screw shaft to snap into engagement with the collet.

In some embodiments, a head assembly includes a snap ring that holds theretainer in the implant receiver. In some embodiments, a head of thescrew shaft component may be assembled to the retainer using a forceand/or interference fit. In some embodiments, the retainer is expandablebetween a capture orientation with the head of the screw shaft and anexpanded orientation. In some embodiments, a head assembly includes acrown, a retainer, a tulip and a snap ring. In some embodiments, a snapring is engaged in a retaining groove in the tulip head andprovisionally engaged to the retainer. In some embodiments, a methodincludes the step of engaging the screw shaft assembly with the headassembly such that the retainer captures the head of the screw shaft andis disposed with the implant receiver in a closed position to create apermanent assembly of a bone fastener.

In some embodiments, the spinal implant system comprises a modularsystem that includes a bone fastener including an array of members, suchas, for example, bone screw shafts that can be selectively coupled tomembers, such as, for example, receivers. In some embodiments, thespinal implant system comprises a selectively coupled bone fastener thatcan be assembled on a surgical table or in-situ. In some embodiments,the selectively coupled bone fastener is assembled with a force of lessthan 50 Newtons (N). In some embodiments, a bone fastener assemblycomprises manually engaging the screw shaft in a pop-on engagement withthe head/receiver of the bone fastener. In some embodiments, a forcerequired to manually engage a screw shaft with a head/receiver of thebone fastener is in a range of 2 to 50 N. In some embodiments, a forcerequired to manually engage a screw shaft with a head/receiver of thebone fastener is in a range of 5 to 10 N. In some embodiments, a screwshaft is manually engaged with a head/receiver of the bone fastener, asdescribed herein, such that removal of the head/receiver from the screwshaft requires a force and/or a pull-out strength of at least 5000 N.

In some embodiments, the present disclosure may be employed to treatspinal disorders such as, for example, degenerative disc disease, discherniation, osteoporosis, spondylolisthesis, stenosis, scoliosis andother curvature abnormalities, kyphosis, tumor and fractures. In someembodiments, the present disclosure may be employed with other ostealand bone related applications, including those associated withdiagnostics and therapeutics. In some embodiments, the disclosed spinalimplant system may be alternatively employed in a surgical treatmentwith a patient in a prone or supine position, and/or employ varioussurgical approaches to the spine, including anterior, posterior,posterior mid-line, lateral, postero-lateral, and/or antero-lateralapproaches, and in other body regions. The present disclosure may alsobe alternatively employed with procedures for treating the lumbar,cervical, thoracic, sacral and pelvic regions of a spinal column. Thespinal implant system of the present disclosure may also be used onanimals, bone models and other non-living substrates, such as, forexample, in training, testing and demonstration.

The present disclosure may be understood more readily by reference tothe following detailed description of the embodiments taken inconnection with the accompanying drawing figures, which form a part ofthis disclosure. It is to be understood that this application is notlimited to the specific devices, methods, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular embodiments by way of exampleonly and is not intended to be limiting. In some embodiments, as used inthe specification and including the appended claims, the singular forms“a,” “an,” and “the” include the plural, and reference to a particularnumerical value includes at least that particular value, unless thecontext clearly dictates otherwise. Ranges may be expressed herein asfrom “about” or “approximately” one particular value and/or to “about”or “approximately” another particular value. When such a range isexpressed, another embodiment includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about,” it willbe understood that the particular value forms another embodiment. It isalso understood that all spatial references, such as, for example,horizontal, vertical, top, upper, lower, bottom, left and right, are forillustrative purposes only and can be varied within the scope of thedisclosure. For example, the references “upper” and “lower” are relativeand used only in the context to the other, and are not necessarily“superior” and “inferior”.

As used in the specification and including the appended claims,“treating” or “treatment” of a disease or condition refers to performinga procedure that may include administering one or more drugs to apatient (human, normal or otherwise or other mammal), employingimplantable devices, and/or employing instruments that treat thedisease, such as, for example, microdiscectomy instruments used toremove portions bulging or herniated discs and/or bone spurs, in aneffort to alleviate signs or symptoms of the disease or condition.Alleviation can occur prior to signs or symptoms of the disease orcondition appearing, as well as after their appearance. Thus, treatingor treatment includes preventing or prevention of disease or undesirablecondition (e.g., preventing the disease from occurring in a patient, whomay be predisposed to the disease but has not yet been diagnosed ashaving it). In addition, treating or treatment does not require completealleviation of signs or symptoms, does not require a cure, andspecifically includes procedures that have only a marginal effect on thepatient. Treatment can include inhibiting the disease, e.g., arrestingits development, or relieving the disease, e.g., causing regression ofthe disease. For example, treatment can include reducing acute orchronic inflammation; alleviating pain and mitigating and inducingre-growth of new ligament, bone and other tissues; as an adjunct insurgery; and/or any repair procedure. Also, as used in the specificationand including the appended claims, the term “tissue” includes softtissue, ligaments, tendons, cartilage and/or bone unless specificallyreferred to otherwise.

The following discussion includes a description of a surgical systemincluding a bone fastener, related components and methods of employingthe surgical system in accordance with the principles of the presentdisclosure. Alternate embodiments are also disclosed. Reference is madein detail to the exemplary embodiments of the present disclosure, whichare illustrated in the accompanying figures. Turning to FIGS. 1-12,there are illustrated components of a spinal implant system 10.

The components of spinal implant system 10 can be fabricated frombiologically acceptable materials suitable for medical applications,including metals, synthetic polymers, ceramics and bone material and/ortheir composites. For example, the components of spinal implant system10, individually or collectively, can be fabricated from materials suchas stainless steel alloys, commercially pure titanium, titanium alloys,Grade 5 titanium, super-elastic titanium alloys, cobalt-chrome alloys,superelastic metallic alloys (e.g., Nitinol, super elasto-plasticmetals, such as GUM METAL®), ceramics and composites thereof such ascalcium phosphate (e.g., SKELITE™), thermoplastics such aspolyaryletherketone (PAEK) including polyetheretherketone (PEEK),polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEKcomposites, PEEK-BaSO₄ polymeric rubbers, polyethylene terephthalate(PET), fabric, silicone, polyurethane, silicone-polyurethane copolymers,polymeric rubbers, polyolefin rubbers, hydrogels, semi-rigid and rigidmaterials, elastomers, rubbers, thermoplastic elastomers, thermosetelastomers, elastomeric composites, rigid polymers includingpolyphenylene, polyimide, polyimide, polyetherimide, polyethylene,epoxy, bone material including autograft, allograft, xenograft ortransgenic cortical and/or corticocancellous bone, and tissue growth ordifferentiation factors, partially resorbable materials, such as, forexample, composites of metals and calcium-based ceramics, composites ofPEEK and calcium based ceramics, composites of PEEK with resorbablepolymers, totally resorbable materials, such as, for example, calciumbased ceramics such as calcium phosphate, tri-calcium phosphate (TCP),hydroxyapatite (HA)-TCP, calcium sulfate, or other resorbable polymerssuch as polyaetide, polyglycolide, polytyrosine carbonate,polycaroplaetohe and their combinations.

Various components of spinal implant system 10 may have materialcomposites, including the above materials, to achieve various desiredcharacteristics such as strength, rigidity, elasticity, compliance,biomechanical performance, durability and radiolucency or imagingpreference. The components of spinal implant system 10, individually orcollectively, may also be fabricated from a heterogeneous material suchas a combination of two or more of the above-described materials. Thecomponents of spinal implant system 10 may be monolithically formed,integrally connected or include fastening elements and/or instruments,as described herein.

Spinal implant system 10 includes a spinal implant, such as, forexample, a bone fastener 180. Bone fastener 180 comprises a member, suchas, for example, a screw shaft 12 and a head assembly 13. In someembodiments, screw shaft 12 and head assembly 13 are assembled in situor prior to implant to form bone fastener 180, as described herein.

Head assembly 13 includes a member, such as, for example, a receiver 14.Receiver 14 extends along and defines an axis X1. Receiver 14 includes apair of spaced apart arms 16, 18 that define an implant cavity 20therebetween configured for disposal of a component of a spinalconstruct, such as, for example, a spinal rod (not shown).

Arms 16, 18 each extend parallel to axis X1. In some embodiments, arm 16and/or arm 18 may be disposed at alternate orientations, relative toaxis X1 such as, for example, transverse, perpendicular and/or otherangular orientations such as acute or obtuse, coaxial and/or may beoffset or staggered. Arms 16, 18 each include an arcuate outer surfaceextending between a pair of side surfaces. At least one of the outersurfaces and the side surfaces of arms 16, 18 have at least one recessor cavity therein configured to receive an insertion tool, compressioninstrument and/or instruments for inserting and tensioning bone fastener180. In some embodiments, arms 16, 18 are connected at proximal anddistal ends thereof such that receiver 14 defines a closed spinal rodslot.

Cavity 20 is substantially U-shaped. In some embodiments, all or only aportion of cavity 20 may have alternate cross section configurations,such as, for example, closed, V-shaped, W-shaped, oval, oblongtriangular, square, polygonal, irregular, uniform, non-uniform, offset,staggered, and/or tapered. Receiver 14 includes an inner surface 22. Aportion of surface 22 includes a thread form 24 located adjacent arm 16and a thread form 26 located adjacent arm 18. Thread forms 24, 26 areeach configured for engagement with a coupling member, such as, forexample, a setscrew (not shown), to retain the spinal rod within cavity20. In some embodiments, surface 22 may be disposed with the couplingmember in alternate fixation configurations, such as, for example,friction fit, pressure fit, locking protrusion/recess, locking keywayand/or adhesive. In some embodiments, all or only a portion of surface22 may have alternate surface configurations to enhance engagement withthe spinal rod and/or the setscrew, such as, for example, rough,arcuate, undulating, mesh, porous, semi-porous, dimpled and/or textured.In some embodiments, receiver 14 may include alternate configurations,such as, for example, closed, open and/or side access.

Receiver 14 includes a surface 30. Surface 30 defines a cavity, such as,for example, a circumferential groove 34 configured for disposal of aband, such as, for example, a circumferential ring 36. In someembodiments, ring 36 comprises a flexible snap ring. In someembodiments, ring 36 includes a selected height and a selected width.Ring 36 includes a circumference that extends between ends of ring 36.In some embodiments, the ends define an opening, such as, for example, agap. In some embodiments, the gap is sized such that the gap has athickness that is less than the height and the width. In someembodiments, upon disposal of ring 36 with groove 34, the surface ofgroove 34 resists and/or prevents axial translation of ring 36 relativeto axis X1. In some embodiments, ring 36 facilitates provisionalassembly of the components of head assembly 13, as described herein.

Receiver 14 includes a surface 40. Surface 40 defines a channel 42.Channel 42 is configured for disposal of a part, such as, for example, acrown 44, as described herein. In some embodiments, channel 42 isseparated from surface 22 by a protrusion, such as, for example, a lip48. In some embodiments, lip 48 is configured as a stop surface to limittranslation of crown 44. In some embodiments, all or only a portion ofsurfaces 30, 40 may have alternate surface configurations, such as, forexample, rough, arcuate, undulating, mesh, porous, semi-porous, dimpledand/or textured.

Receiver 14 includes a surface 50. Surface 50 includes a threadedsurface 52. In some embodiments, surface 52 may include a single threadturn or a plurality of discrete threads. Surface 52 is configured for athreaded engagement with a surface of a retainer, such as, for example,a collet 90, as described herein. Engagement of surface 52 with asurface of collet 90 is configured to translate collet 90 between anopen position for engaging and connecting with screw shaft 12 and aclosed position to fix position of collet 90 and/or screw shaft 12 withreceiver 14, and/or assemble the components of bone fastener 180 in afixed connection, as described herein. In some embodiments, bonefastener 180 may be assembled for permanent assembly and/or an assembledconfiguration that may be revised.

Crown 44 is configured for disposal within cavity 20 and channel 42.Crown 44 includes a wall 66 having an end surface 68 and an end surface70. Surface 68 is configured to define at least a portion of cavity 20.Surface 70 defines an engagement portion 78 configured for engagementwith a head 120 of screw shaft 12, as described herein. In someembodiments, engagement portion 78 includes a concave configuration tofacilitate engagement with head 120.

Wall 66 includes a surface 72 and a surface 74. Surface 72 defines acircular opening. In some embodiments, all or only a portion of surface72 may have alternate cross section configurations, such as, forexample, oval, oblong triangular, square, polygonal, irregular, uniform,non-uniform, offset, staggered, and/or tapered.

Surface 72 defines a plurality of mating elements, such as, for example,recesses 76. In some embodiments, surface 72 includes one or a pluralityof recesses 76 disposed circumferentially about surface 72. In someembodiments, recesses 76 include a concave configuration. Recesses 76are configured for a mating engagement with a surgical instrument suchas a driver. Engagement with the surgical instrument facilitatesrotating crown 44 and collet 90 connected therewith for translation ofcollett 90 between the open and closed positions, as described herein.In some embodiments, recesses 76 may have various cross-sectionconfigurations, such as, for example, oval, oblong, triangular,rectangular, square, polygonal, irregular, uniform, non-uniform,variable, tubular and/or tapered. In some embodiments, recesses 76 mayhave various surface configurations, such as, for example, smooth and/orsurface configurations to enhance engagement with the surgicalinstrument, such as, for example, rough, arcuate, undulating, porous,semi-porous, dimpled, polished and/or textured.

Surface 74 defines a plurality of mating elements, such as, for example,flanges 80 extending therefrom. In some embodiments, flange 80 extendssubstantially perpendicular to axis X1. In some embodiments, flange 80may be disposed in various orientations, such as, for example,transverse and/or at angular orientations, such as acute or obtuserelative to axis X1.

In some embodiments, surface 74 includes one or a plurality of flanges80 disposed circumferentially in a spaced apart relation about surface74. In some embodiments, flanges 80 include a convex configuration. Insome embodiments, all or only a portion of flanges 80 may have alternateconfigurations, such as, for example, oval, oblong, triangular, square,polygonal, irregular, uniform, non-uniform, offset, staggered, and/ortapered.

Flanges 80 are configured for a mating engagement with collet 90, asdescribed herein. Flanges 80 engage a surface of collet 90 tosimultaneously rotate collet 90 to drive and translate crown 44 andcollet 90. In some embodiments, collet 90 is rotated 180 degrees totranslate collet 90 between the open and closed positions, as describedherein.

Collet 90 includes a wall, such as, for example, a circumferentialsleeve 92. Sleeve 92 includes an end surface 94 and an end surface 96.Sleeve 92 includes a surface 98 and a surface 100. Surface 94 defines acircular opening configured for disposal of head 120. In someembodiments, all or only a portion of surface 94 may have alternatecross section configurations, such as, for example, oval, oblongtriangular, square, polygonal, irregular, uniform, non-uniform, offset,staggered, and/or tapered.

Surface 94 defines a plurality of mating elements, such as, for example,notches 102. In some embodiments, surface 94 includes one or a pluralityof notches 102 disposed circumferentially about surface 94. In someembodiments, notches 102 include a concave configuration. In someembodiments, all or only a portion of notches 102 may have alternateconfigurations, such as, for example, oval, oblong, triangular, square,polygonal, irregular, uniform, non-uniform, offset, staggered, and/ortapered. Notches 102 matingly engage flanges 80. Engagement of flanges80 with notches 102 connects crown 44 and collet 90 such that crown 44drives and rotates collet 90 to translate collet 90 between an openposition for engaging and connecting with screw shaft 12 and a closedposition to fix position of collet 90 and/or screw shaft 12 withreceiver 14, as described herein. In some embodiments, collet 90 can bemated with crown 44 in various configurations, such as, for example,threaded connection, clips, dovetail connection, key/keyslot, frictionfit, pressure fit, interlocking engagement, dovetail connection, hookand loop closure, clips, barbs, tongue in groove, threaded, magnetic,key/keyslot, drill chuck and/or adhesive.

Sleeve 92 includes a surface that defines gaps, such as, for example, aplurality of spaced apart slots 108 that extend through the wall ofsleeve 92. Slots 108 extend along a portion of sleeve 92 and aredisposed circumferentially about sleeve 92. Slots 108 provideflexibility to sleeve 92 and are configured to facilitate expansionand/or contraction of collet 90, as described herein. In someembodiments, sleeve 92 can include one or a plurality of slots 108. Insome embodiments, one or more slots 108 may have alternateconfigurations, such as, for example, irregular, uniform, non-uniform,offset, staggered, and/or tapered.

Slots 108 provide flexibility to sleeve 92 such that collet 90 includesan expandable orientation, as shown in FIGS. 10 and 11, and anon-expandable orientation, as shown in FIG. 12. For example, screwshaft 12 is engageable with collet 90 such that slots 108 facilitate asnap fit engagement of collet 90 with head 120. As such, sleeve 92expands upon engagement with head 120 so that head 120 can slide throughthe opening of surface 94 and the cavity of surface 98, and sleeve 92contracts or snap fits around head 120 for connection therewith. In someembodiments, surface 98 may be disposed with head 120 in alternatefixation configurations, such as, for example, friction fit, pressurefit, locking protrusion/recess, locking keyway and/or adhesive.

Surface 100 includes a threaded surface 114. In some embodiments,surface 114 may include a single thread turn or a plurality of discretethreads. Surface 114 is configured for a threaded engagement withsurface 52 of receiver 14, as described herein. Engagement of surfaces52, 114 is configured to translate collet 90 axially between an openposition for engaging and connecting with screw shaft 12 and a closedposition to fix position of collet 90 and/or screw shaft 12 withreceiver 14, as described herein.

Surface 100 defines a cavity, such as, for example, a groove 110 fordisposal of ring 36 with groove 34. In some embodiments, groove 110extends about all or a portion of surface 100. With ring 36 disposedwith grooves 34, 110, ring 36 is engageable with threads 114 to resistand/or prevent disassembly of collet 90 and/or crown 44 from receiver14, in the open position, as described herein. As such, ring 36 engagescollet 90 for provisional connection and assembly of the components ofhead assembly 13.

Collet 90 includes a circumferential flange 112. In some embodiments,alignment of groove 34 and flange 112 captures ring 36 between collet 90and receiver 14 to facilitate assembly of the components of headassembly 13.

Screw shaft 12 includes head 120 and a shaft 122. Head 120 includes atool engaging portion 124 configured to engage a surgical tool orinstrument, as described herein. In some embodiments, portion 124includes a hexagonal cross-section to facilitate engagement with asurgical tool or instrument, as described herein. In some embodiments,portion 124 may have alternative cross-sections, such as, for example,rectangular, polygonal, hexalobe, oval, or irregular. In someembodiments, head 120 includes a surface 126 that defines a plurality ofridges 128 to improve purchase of head 120 with crown 44. In someembodiments, head 120 includes an outer surface. In some embodiments,the outer surface includes planar surfaces, such as, for example, flatsand arcuate surfaces. Head 120 is configured for attachment with collet90 of head assembly 13, as described herein. Shaft 122 is configured topenetrate tissue, such as, for example, bone. In some embodiments, shaft122 includes an outer surface having an external thread form. In someembodiments, the external thread form may include a single thread turnor a plurality of discrete threads.

Collet 90 is translatable with crown 44 and relative to the componentsof head assembly 13, for example, the inner surface of receiver 14,between an open position and an expandable orientation, as shown inFIGS. 10 and 11, for engaging and connecting with screw shaft 12 and aclosed position and a non-expandable orientation, as shown in FIG. 12,to fix position of collet 90 and/or screw shaft 12 with receiver 14 inan assembly of the components of bone fastener 180.

For example, crown 44 is connected with collet 90 such that flanges 80are mated with notches 102. Collet 90 is threaded with surface 52 ofreceiver 14, such that the assembly of collet 90/crown 44 is disposedwith cavity 20, as described herein. The assembly of collet 90/crown 44can be pre-assembled and/or a surgical driver can engage recesses 76 torotate collet 90/crown 44, for example, in a clockwise direction,relative to receiver 14 for translation to an open position, as shown inFIG. 10. Ring 36 is disposed with grooves 34, 110 and is engageable withthreads 114 to resist and/or prevent dis-assembly of collet 90/crown 44from receiver 14, in the open position, and provisionally fix thecomponents of head assembly 13. Flange 112 extends from an end surface56 of receiver 14 and collet 90 is expandable, as described herein, tofacilitate connection with screw shaft 12.

Screw shaft 12 and head assembly 13 are engaged, in the direction shownby arrows A in FIG. 10, for assembly of the components of bone fastener180. Sleeve 92 expands upon engagement with head 120 and head 120 slidesinto the cavity of surface 98. Sleeve 92 contracts around head 120, asshown in FIG. 11, to provide a snap fit assembly of collet 90 and screwshaft 12.

A surgical driver engages recesses 76 and rotates crown 44, for example,180 angular degrees in a counter-clockwise direction, to simultaneouslydrive and rotate collet 90. Such rotation of collet 90 threads andtranslates collet 90 relative to receiver 14 to a closed position, asshown in FIG. 12. Crown 44 engages lip 48 and flange 112 engages ring 36within receiver 14. Surface 50 resists and/or prevents expansion ofcollet 90 such that collet 90 is disposed in a non-expandableorientation with head assembly 13 in the closed position. In the closedposition, collet 90 and/or screw shaft 12 are in fixed position withreceiver 14 in an assembly of the components of bone fastener 180.

In some embodiments, collet 90 is configured to interface head 120 suchthat shaft 122 is fixed relative to receiver 14 forming a fixed axisbone fastener. In some embodiments, surface 98 is configured tointerface head 120 such that shaft 122 rotatable about multiple axesrelative to receiver 14. In some embodiments, shaft 122 is rotatable inone or a plurality of planes relative to receiver 14, similar to thatdescribed herein, and/or rotatable about axis X1 in an angular range of360 degrees. In some embodiments, assembly of screw shaft 12 and headassembly 13 forms a multi-axial bone fastener. In some embodiments,shaft 122 is rotatable in a plane, such as, for example, a sagittalplane relative to receiver 14 forming a sagittal adjusting bonefastener.

In some embodiments, manual engagement and/or non-instrumented assemblyof collet 90 and screw shaft 12 includes coupling without use ofseparate and/or independent instrumentation engaged with screw shaft 12components to effect a provisional assembly. In some embodiments, manualengagement and/or non-instrumented assembly includes a practitioner,surgeon and/or medical staff grasping collet 90 and screw shaft 12 andforcibly assembling the components. In some embodiments, collet 90 maybe previously assembled with receiver 14 and/or crown 44. In someembodiments, manual engagement and/or non-instrumented assembly includesa practitioner, surgeon and/or medical staff grasping collet 90 andscrew shaft 12 and forcibly snap fitting the components together, asdescribed herein. In some embodiments, manual engagement and/ornon-instrumented assembly includes a practitioner, surgeon and/ormedical staff grasping collet 90 and screw shaft 12 and forcibly popfitting the components together and/or pop fitting collet 90 onto screwshaft 12, as described herein.

In some embodiments, a force in a range of 2-50 N is required tomanually engage collet 90 and screw shaft 12 and forcibly assemble thecomponents. For example, a force in a range of 2-50 N is required tosnap fit and/or pop fit assemble collet 90 and screw shaft 12. In someembodiments, a force in a range of 5-10 N is required to manually engagecollet 90 and screw shaft 12 and forcibly assemble the components. Forexample, a force in a range of 5-10 N is required to snap fit and/or popfit assemble collet 90 and screw shaft 12. In some embodiments, screwshaft 12 is manually engaged with collet 90 in a non-instrumentedassembly, as described herein, such that removal of collet 90 and screwshaft 12 requires a force and/or a pull-out strength of at least 5000 N.In some embodiments, this configuration provides manually engageablecomponents that are assembled without instrumentation, and subsequent toassembly, the assembled components have a selected pull-out strengthand/or can be pulled apart, removed and/or separated with a minimumrequired force.

In some embodiments, spinal implant system 10 comprises a spinal implantkit, as described herein, which includes a plurality of screw shafts 12,crowns 44, collets 90 and receivers 14 to comprise a selected bonefastener configuration and/or selected movement, as described herein. Insome embodiments, the components of spinal implant system 10 areinterchangeable.

In assembly, operation and use, spinal implant system 10, similar to thesystems and methods described herein, includes a screw shaft 12 forconnection with a head assembly 13, and is employed with a surgicalprocedure for treatment of a spinal disorder affecting a section of aspine of a patient, as discussed herein. Spinal implant system 10 isemployed with a surgical procedure for treatment of a condition orinjury of an affected section of the spine.

In some embodiments, spinal implant system 10 includes a screw shaft 12for connection with a head assembly 13 forming bone fastener 180 havinga selected movement, as described herein. Bone fastener 180 and one or aplurality of spinal implants, such as, for example, spinal rods can bedelivered or implanted as a pre-assembled device or can be assembled insitu. The components of spinal implant system 10 may be may becompletely or partially revised, removed or replaced. In someembodiments, a screw shaft 12 is interchangeable with head assembly 13to comprise a bone fastener 180 having a selected movement, such as, forexample, multi-axial movement, sagittal angulation movement, fixed axismovement, mono-axial movement and/or uni-planar movement.

For example, a crown 44 and a collet 90 are mated to comprise a selectedbone fastener configuration and/or movement with a receiver 14. Apre-assembly of collet 90/crown 44 is disposed with cavity 20, asdescribed herein. A surgical driver rotates collet 90/crown 44, forexample, in a clockwise direction, relative to receiver 14 fortranslation to an open position, as shown in FIG. 10. Ring 36 resistsand/or prevents dis-assembly of collet 90/crown 44 from receiver 14, inthe open position, and provisionally fixes the components of headassembly 13. Screw shaft 12 and head assembly 13 are engaged, in thedirection shown by arrows A in FIG. 10, for assembly of the componentsof bone fastener 180. Sleeve 92 expands upon engagement with head 120and head 120 slides into the cavity of surface 98. Sleeve 92 contractsaround head 120, as shown in FIG. 11, to provide a snap fit assembly ofcollet 90 and screw shaft 12.

The surgical driver simultaneously drives and rotates collet 90/crown44, for example, in a counter-clockwise direction relative to receiver14. Such rotation of collet 90 threads and translates collet 90 relativeto receiver 14 to a closed position, as shown in FIG. 12. Surface 50resists and/or prevents expansion of collet 90 such that collet 90 isdisposed in a non-expandable orientation with head assembly 13 in theclosed position. In the closed position, collet 90 and/or screw shaft 12are in fixed position with receiver 14 in an assembly of the componentsof bone fastener 180.

In use, for treatment of a spinal disorder, bone fastener 180 includingassembled screw shaft 12 and head assembly 13 can be threaded andengaged with tissue. In some embodiments, the selected bone fastener 180is disposed adjacent vertebrae at a surgical site and is manipulated todrive, torque, insert or otherwise connect shaft 122 with vertebrae inconnection with a surgical procedure, as described herein.

In some embodiments, spinal implant system 10 includes an agent, whichmay be disposed, packed, coated or layered within, on or about thecomponents and/or surfaces of spinal implant system 10. In someembodiments, the agent may include bone growth promoting material, suchas, for example, bone graft to enhance fixation of the fixation elementswith vertebrae. In some embodiments, the agent may be HA coating. Insome embodiments, the agent may include one or a plurality oftherapeutic agents and/or pharmacological agents for release, includingsustained release, to treat, for example, pain, inflammation anddegeneration.

In some embodiments, the use of microsurgical and image guidedtechnologies may be employed to access, view and repair spinaldeterioration or damage, with the aid of spinal implant system 10. Thecomponents of spinal implant system 10 can be made of radiolucentmaterials such as polymers. Radiomarkers may be included foridentification under x-ray, fluoroscopy, CT or other imaging techniques.

In some embodiments, spinal implant system 10 can include one or aplurality of bone fasteners 180 such as those described herein and/orfixation elements, which may be employed with a single vertebral levelor a plurality of vertebral levels. In some embodiments, bone fasteners180 may be engaged with vertebrae in various orientations, such as, forexample, series, parallel, offset, staggered and/or alternate vertebrallevels. In some embodiments, bone fasteners 180 may be configured asmulti-axial screws, sagittal angulation screws, pedicle screws,mono-axial screws, uni-planar screws, fixed screws, anchors, tissuepenetrating screws, conventional screws and/or expanding screws. In someembodiments, bone fasteners 180 may be employed with wedges, anchors,buttons, clips, snaps, friction fittings, compressive fittings,expanding rivets, staples, nails, adhesives, connectors, fixation platesand/or posts.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplification of thevarious embodiments. Those skilled in the art will envision othermodifications within the scope and spirit of the claims appended hereto.

What is claimed is:
 1. A bone fastener comprising: a first member defining an implant cavity and having a threaded inner surface; a part disposed with the first member; a retainer connected with the part and the first member, and including a threaded outer surface configured for engagement with the threaded inner surface of the first member to move the retainer between an expandable orientation and a non-expandable orientation; and a second member connectable to the retainer and configured to penetrate tissue, wherein the first member defines a groove configured for disposal of a band, and wherein the retainer is engageable with the part and the first member in the expandable orientation such that the retainer engages the band to provisionally connect the retainer with the first member and in the non-expandable orientation such that the retainer is fixed with the first member.
 2. A bone fastener as recited in claim 1, wherein the part includes at least one mating element that interfaces with a surgical instrument for rotation thereof.
 3. A bone fastener as recited in claim 1, wherein the part includes an inner surface that defines a plurality of circumferentially disposed recesses.
 4. A bone fastener as recited in claim 1, wherein the part includes a plurality of spaced apart flanges that matingly engage notches in the retainer to connect the part and the retainer such that the part drives and rotates the retainer between the expandable orientation and the non-expandable orientation.
 5. A bone fastener as recited in claim 1, wherein the part includes spaced apart circumferential outer flanges engageable with the retainer.
 6. A bone fastener as recited in claim 1, wherein the retainer is simultaneously rotatable with the part.
 7. A bone fastener as recited in claim 1, wherein the retainer is rotatable relative to the first member for fixation therewith.
 8. A bone fastener as recited in claim 1, wherein the part includes an outer surface that is free of threads.
 9. A bone fastener as recited in claim 1, wherein the retainer is expandable between a capture orientation with the second member and an expanded orientation.
 10. A bone fastener as recited in claim 1, wherein the retainer includes a circumferential sleeve that defines at least one gap.
 11. A bone fastener as recited in claim 1, wherein the retainer defines a plurality of spaced apart concave notches and the part comprises a plurality of spaced apart convex flanges that matingly engage the notches to connect the part and the retainer such that the part drives and rotates the retainer between the expandable orientation and the non-expandable orientation.
 12. A bone fastener as recited in claim 1, wherein the retainer is manually engageable with the second member in a non-instrumented assembly.
 13. A bone fastener as recited in claim 1, wherein the second member is spaced apart from the first member by the part and the retainer.
 14. A bone fastener as recited in claim 1, wherein the retainer comprises opposite proximal and distal surfaces, the proximal surface directly engaging a shoulder of the first member when the retainer is in the non-expandable orientation to prevent the retainer from translating axially relative to the first member in one direction.
 15. A bone fastener as recited in claim 1, wherein the part comprises opposite proximal and distal surfaces, the proximal surface directly engaging a shoulder of the first member when the retainer is in the non-expandable orientation to prevent the part from translating axially relative to the first member in one direction.
 16. A bone fastener comprising: an implant receiver; a crown disposed with the implant receiver; a collet connected with the crown and including a threaded outer surface configured for engagement with a threaded inner surface of the implant receiver to translate the collet relative to the implant receiver between an open position and a closed position; and a screw shaft engageable with the collet and configured to penetrate tissue, wherein the implant receiver defines a groove configured for disposal of a band, and wherein the collet is engageable with the crown and the implant receiver in the open position such that the collet engages the band to provisionally connect the collet with the implant receiver and in the closed position such that the collet is fixed with the implant receiver.
 17. A bone fastener as recited in claim 16, wherein the collet is expandable between a capture orientation with the screw shaft and an expanded orientation.
 18. A bone fastener as recited in claim 16, wherein the collet is simultaneously rotatable with the crown.
 19. A bone fastener comprising: an implant receiver; a crown disposed with the implant receiver, the crown including an inner surface that mates with a surgical instrument and outer flanges; a collet comprising notches engaged with the flanges to connect the crown and the collet such that the crown drives and rotates the collet between an expandable orientation and a non-expandable orientation, the collet comprising a threaded outer surface configured for engagement with a threaded inner surface of the implant receiver to translate the collet relative to the implant receiver between the expandable orientation and the non-expandable orientation; and a screw shaft connectable to the collet and configured to penetrate tissue, wherein the implant receiver defines a groove configured for disposal of a band, and wherein the collet is engageable with the crown and the implant receiver in the expandable orientation such that the collet engages the band to provisionally connect the collet with the first member.
 20. A bone fastener as recited in claim 19, wherein the collet is engageable with the crown and the implant receiver in the non-expandable orientation such that the collet is fixed with the implant receiver. 